Liverpool manager Jurgen Klopp says Roberto Firmino may return from an ankle injury to face Everton on Sunday in a vital clash for the Premier League leaders.

Everton, in ninth place, have not beaten Liverpool since 2010 but would dearly love to spoil their neighbours' bid to end a 29-year wait to win the title.

Firmino missed Wednesday's 5-0 victory over Watford as Klopp's men clicked back into gear following a run of four draws in five games.

The Brazilian has returned to training and has a history of healing quickly.

"He was out there in the running yesterday but we have to see how he reacts," said Klopp.

"He is very positive, that's Bobby's nature. We have to see. I don't see any other player -- OK, we have maybe two or three more of them -- being even in contention for that game after the little problem he had.

"It looks really good but if he will be ready for Sunday, I don't know in this second."

All five of Liverpool's goals at Anfield in midweek came from assists by full-backs Trent Alexander-Arnold and Andy Robertson.

Klopp revealed that Alexander-Arnold had taken the match ball home with him -- a tradition normally reserved from the scorer of hat-tricks -- after his three assists.

"That game was exceptional. I don't think I was ever part of a game that somebody had a hat-trick of assists," added the German coach.

And Klopp acknowledged how important the young full-back pairing is, not only to Liverpool's improved defensive record this season, but as a potent creative weapon going forward.

"It's important. That's modern football. If you ask a young boy his favourite position, I don't think a lot of boys would say 'I want to be a full-back'. But football changed, they became much more important," he added.

"I was a full-back myself for a decent part of my career. It didn't look completely different to what the boys are doing but I know there are a lot of things to do.

"You have to be really strong defensively but on the other hand, because a lot of teams clear the wing for the full-backs offensively, if you are then able to be open-minded enough and have the football quality to see some people in the same shirt in the box, that helps a lot."